EBay Inc warned that 2008 results would fall below Wall Street expectations, sending its shares more than 5 percent, even as it confirmed long-serving Chief Executive Meg Whitman would step aside. The warning accompanied solid fourth-quarter results, and analysts said it was unclear if the company feared an economic slowdown or whether management was giving itself room to make changes to revitalize the business. Growth in the main auction business has slowed during most of the past three years.

Auctions chief John Donahoe will take over from Whitman at the end of March. He told a conference call with investors that eBay would cut sellers' fees, which would reduce revenue temporarily, but stimulate long-term growth. Overall growth in e-commerce will slow in 2008, executives cautioned.